8. Los Angeles Rams – 1975

Several teams in NFL history have had a defensive line nicknamed the "Fearsome Foursome," but no team lived up to this moniker better than the ’75 Rams. Led by terrifying tackler Jack Youngblood, the Rams cruised to a 12-2 record — all the while allowing an average of just 9.6 points a game, one of the top marks in NFL history. Over the final six regular season games, Los Angeles’ opponents scored an average of just 5.3 points a game.